This invention relates generally to furnaces for the burning of used oil and, more particularly, to a preheater block for use in conjunction with multi oil furnaces to improve the control of the burning of used oil therein.
Multi oil furnaces are similar to standard oil burning furnaces, but have been adapted to handle oil products that have been previously used in a traditional lubricating operation. Such oil products can have significantly varying viscosities and significantly varying burning characteristics, as well. Typically, used oil products are collected into a tank to be supplied to the furnace from a single source. As furnaces are normally operated when the ambient air temperatures are sufficiently cold to warrant the use of the furnace, the supply of used oil to the furnace is normally as cold as the ambient temperature.
The supply of cold used oil to the furnace provides several problems with respect to regulating the flow of the used oil to the furnace and oil regulators have been provided to control the rate of flow. As the temperature of the supply of used oil decreases, the viscosity of the oil lowers. Further complicating the control of the rate of flow is the changing of the natural viscosity of the oil product itself, as the various oil products do not normally become homogeneously mixed in the storage tank, but rather stay segregated in the order in which they were introduced into the tank.
Accordingly, a setting of the oil flow regulator at an appropriate position to provide an acceptable flame, and therefore an acceptably efficient burning of the oil product, in the burner chamber will result in a unacceptable flame in the burner chamber as the temperature of the used oil changes or as the type of used oil product changes. The resultant change could be either an over-firing of the burner chamber, which can result in a destructive deterioration of the furnace and furnace components, or an under-firing of the burner chamber, which can result in an inefficient burning of the oil products and a polluting of the air.
A pre-heating of the used oil before being introduced into the burner chamber has been devised. The known preheater block has utilized a heating element into the flow path of the used oil into the burner chamber. The direct heating of the oil products results in a residue build-up of the heating element, requiring a periodic replacement of the heating element to maintain the effectiveness thereof. Even with the preheating of the used oil, the regulation of the flow of cold used oil into the preheater for introduction into the burner chamber remained dependent on the temperature fluctuations of the used oil supply.
Accordingly, it would be desirable to provide a multi oil preheating mechanism that would improve the operation of the multi oil furnace, particularly by improving the capability of regulating the flow of used oil to the burner chamber.